The LS comes with 9:5:1 compression, I have heard that raising the compression t0 11:5:1 with .25 over ITR pistons will only give me an extra 5hp! WTF! Is this true? I was thinking that number should be closer to 15hp

 

Raising compression one full percentage point (i.e 10:1 to 11:1) will give you approx. a 4-5% increase in power. So on a stock non-vtec teg is 140hp it will be around 6-7hp give or take. So by you raising compression two full percentage points you should see about a 8-9% increase in hp and torque.

 

So if I was making 160 to the wheels now, and raise my compression to 11:5:1, I would get 160+16=176?

 

Ive heard each point of compression equals about 3-4% more power.

So 2 points equals 8% gain..so around 13 WHP. Thats *should* be across the powerband though..not just peak...so it would be quite noticable.

 

I am looking at spending about $1200 to do this.......would you do it if you were me?

 

yeah thats what the rsx type S and the celica gts are doing to acheive better
powerbands both have 11.pts of compression really high

soo with raising compression a full point.
u gain all 3-4% everywhere, how much faster would u go
1/4 times?



[Modified by bommiE, 10:16 PM 11/6/2001]

 

I'd say hold off and buy a Drag III turbo kit. You can keep your lower compression and get a much more favorable increase in horsepower.

 

I've always wondered myself if you add the percentage increase to your original stock HP and torque or from the amount of hp and tq you are presently making? Can anyone else shed some light on this?

 

If I were you, I'd go all motor, go for the high compression, balance and blueprint the block, crower rods, and wiesco pistons... a bore over wouldn't be a bad idea either

 

I already have a turbo, I love NA myself. Here's the pricelist so far

ITR .25 over pistons new-$425
installing my Eagle rods to the ITR's boring the head and dyno tuning-$750

Why are Wiseco's, JE or Arias better than OEM ITR?

 

all of those aftermarket pistons you named are better because they are all FORGED aluminum, and all of the honda OEM pistons are CAST aluminum. they just dissipate heat better, therfore making it stronger underboost, compression, or nos. if you have the cash forged is THE way to go.
ADAM

 

You don't need forged if your n/a.. CTR pistons would work fine. Compression not only gives hp but it gives the torque that these torqueless motors have. Results vary and gains can be more than 3-4% depends on tuning. Depends on what cam you use.

 

Ya, I wonder about that too. I think that different mods would respond differently to increased compression, if only by a couple percent, but thats just a guess.

 

This is what i found....as taken from sho...posted by Tuan


The relationship between thermodynamic efficiency and CR is both directly exponential and inverted exponential...look at the Otto cycle equation. In hp terms we see a 1% gain per 0.1:1 increase in CR.
http://web.mit.edu/16.unified/www/F...s/chapter_5.htm http://www.superhonda.org/board/show...ht=compression

i dont really understand the formula, but maybe some one here does, also i dont know if it matters if you use whp or flywheel hp

anyways for example in my ls whp before is 130, i am going up to 12.5:1 CR, so by that formula i will be making and extra 39hp, for a total of 169

i will let you know my actuall hp in about a month or so when i get the car dynoed

 

What about the jdm gsr motor, its makes 10.6 right? And the usdm one is 10.0. The jdm has 10 extra horsepower. What else beside compression makes it have more? I thought thats why the jdm motor had more power becuase of compression.

 

that jdm motor has a better header and is probably tuned more aggressively as well.

 

The only difference is +0.6 more compression and ECU (JDM vs. USDM)

 

LS motor has 9.2 to 1 compression ratio

Tom


[Modified by Tomakit, 2:45 PM 11/12/2001]